A new monarch for Australia?

While monarchists toast the impending birth of a baby who could create royal history, republicans are wondering whether he, or she, will ever reign over Australia.

If Prince William and his wife Catherine's first child, due around the middle of next year, is a girl, she will be set to make history.

The sex of the baby for once won't matter, in terms of royal succession, following legal changes agreed by all commonwealth countries last year and announced by British Prime Minister David Cameron.

Whether a boy or girl, the new baby will become third in line to the British throne after Prince Charles and Prince William, relegating William's brother Harry to fourth.

But Australian republicanism might affect the extent of the new baby's ultimate dominion.

Republican fever has gone off the boil since the defeat of the 1999 referendum, but is expected to resurface after the end of Elizabeth II's reign.

So whether Australia remains under the umbrella of monarchy long enough for the succession of the new baby, or even for Prince Charles to become king, is a moot point.

When Charles visited Australia last month with his wife Camilla to celebrate the Queen's diamond jubilee, republicans said 48 per cent of Australians supported a republic, but admitted the issue was a long way off the national agenda.

Australians for a Constitutional Monarchy director Jai Martinkovits summed up the opinion polls by saying the only support for a republic was among middle-aged baby boomers; the elderly were rusted-on monarchists and the young largely couldn't care less.